Protective apparatus



Sept. 28,1926.

' C. J. RODMAN PROTECTIVE APPARATUS Filed April 28, 1923 INVENTOR C/arence 1 R0 Alma/1 WITNESSES:

ATTORNEY Patented Sept 28, 1 926.

CLARENCE J. RODMAN, OF WILKINSBURG,

HOUSE ELECTRIC & MANUFACTURING VANIA. I

' PROTECTIVE Application filed April as,

M invention relates to protective apparatus or tanks or containers, audit has particular relation to valve structures that may be employed in connection with transformers, circuit breakers or other electrical apparatus. y

One object of my invention is to provide a simple and efficient valve structure that may be automaticall controlled to connect the interior of a tan to the atmosphere in accordance with the pressure within the tank.

A second object of my invention is to provide a mechanism of the character above described that is controlled in accordance with the height of a column of liquid that is a measure of the pressure in the tank.

A further object of my invention is to provide a valve mechanism that is operated by a float to open a vent in a containing vessel when the pressure in the tank varies from atmospheric pressure by predetermined values.

In the operation of transformers, circuit breakers and other electrical apparatus in which insulating oils are emplo ed for the purpose of cooling the parts of t e electrical devices, it has been found advisable to isolate the surface of the oil from contact with the atmosphere in order to prevent oxidation of the oil and the absorption of moisture from the air.

It has been found that explosions have occurred in connection with enclosed electrical apparatus by reason of the formation of highly explosive compounds or mixtures as a result of arcs below the surface of the oil. The formation of such explosive mixtures is prevented if oxygen is excluded from the interior of the tanks.

The exclusion of oxygen is of advantage also, in that sludging which results from oxidation of the oil, is prevented. An moisture that may be present in the air within the tanks of transformers of usual construction is absorbed by the oil, and. its insulating properties are correspondingly diminished.

In accordance with the present invention, I provide a valve mechanism that is controlled in accordance with the height of a column of liquid to open or to close a vent in the tank in accordance with the a 7 and a valve structure 8, which PEN N S'YLVLN IA, ASSIGNOB TO WESTING- COMPAN Y, A CORPORATION OF PEN N SYL- arranaros. I

1923. Serial No. 635,402. 7

pressure therein. When the pressure in the tank is below atmospheric pressure, air is drawn into the tank through a compartment in which a suitable deoxidizing and dehydrating material operates to remove substantially all oxygen and moisture from the air, permitting substantially nitrogen only to enter the tank. The interior of the tank is connected to the atmosphere when the pressure in the tank exceeds a predetermined value or is below a second predetermined value.

In the accompanying drawing,

Figural is a view, partially in elevation and partially in section, of a tank with my invention applied thereto; and

Fig. 2 is a similar view of a modification of the valve structure.

Referring particularly to Fig. 1, a tank 1, which may be that of a transformer, circuit breaker or other electrical apparatus, is provided with aquantity of insulating oil, indicated at 2. The illustration of the electrical apparatus is omitted as being unnecessaryto an understanding of the present in vention. A space 3, above the oil, is filled with an inert gas, as will be hereinafter set forth.

A vent 4 in the transformer wall is adapted to be connected. to the atmosphere by means of a pipe 5, a respirator 6, a pipe comprises a hollo piston 9 that is closed at one end.

The piston 9 is provided with openings 11 and 12 that are adapted toregisterwith the opening of pipe 7, as w'ill be hereinafter described.

The 13, having an enlarged outer end 14. The tube 13 is filled with a suitable liquid, such, for example, i

as mercury, hollow float member 15 that is mechanicaly ly connected to the piston 9. The float 15,

which is provided with .a removable cap 16, may contain mercury or other suitable liquid or material in desired quantity to determine the pressure at mechanism operates.

The respirator 6 is. provided with a suitable material for rapidly deoxygenating and dehydrating air passing therethrough, the resulting product being substantially pure *dry nitrogen.

which supports a I which the valve I pipe 5 is also connected to a U-tfibe '5 to the space ture.

The space 3 in the transformer tank 1 may be nitially filled with nitrogen in an suitable manner. For example, the tank ma be substantially filled withoil, a valve 17 eing closed to prevent the the valve mechanism. It ma be assumed that oil has been withdrawn rom the tank by means of the usual drain cock not shown), until the level of the oil is be ow the vent is then below atmospheric pressure, and the column of liquid in the portion 14 of the U-tube 13 has fallen to such level that the opening 11 in the piston 9 registers with the pipe 7. Air then enters the upper end of the valve 8 and passes through the piston 9, opening 11, pipe 7 and respirator 6. Substantially pure nitrogen flows through pipe 3 of the tank. Accordin ly, the space 3 is occupied by an inert gas %nitrogen') that is substantially free from mois- The level of the oil under normal temperature conditions ma be determined by the amount withdrawn rom the tank.

When the transformer or other apparatus is in operation, its temperature increases by reason of the electrical losses in the heating of the windings. The volume of the oil 2 increasescorrespondingly, and the gas withinthe space 3 is placed under pressure. The pressure of the gas correspondingly afiects the height of the column of mercury in the tube 13 to vary the position of the float 15 and the piston 9. tank reaches a desired predetermined value, the opening 12 registers with the opening in the pipe 7 and gas is permitted'to escape therethrough. The predetermined pressure may be of any desired value, but it is preferably notto exceed five pounds per square inch in order that the seams of the containing tank may be not be opened.

When the temperature of the oil 2 de-' creases and the pressure in the tank falls below atmospheric pressure, the float 15 and the piston 9 move downwardly and, when the ressure falls to a redetermined value, air is admitted throng the opening 11 in the manner previously described in connection with the initial preparation for operation. The valve mechanism is preferably adapted to operate when the pressure in the tank is only slightly below atmospheric pressure in order that air may not be drawn throughseams of the tank.

From the foregoing, it will be apparent that the pressure vwithin the tank may be relieved'at any desired value and that an inert gas may be supplied to the tank when the pressure is below atmospheric pressure by any desired amount.

Reference may now be had to Fig. 2, in which a modification of the valve mechanism is illustrated and in which similar reference numerals are employed to designate like oil entering 4. The pressure within the tank' When the pressure in the by varying the quantity parts. The essential difference between the valve mechanism of Fig. 2 and that of Fig. 1 is the substitution of a movable weight member 19 for the hollow piston 9 in Fig. 1. The valve member 19 is connected to an intermediate portion of a lever arm20 that has a lost-motion connection at one end to a stationary member 21 and that is connected at its other end to a float member 15. A

stop member 22 serves as a fulcrum for the lever 20 when the float member 15 falls by reason ofrdecreasing pressure within the tank.

' When the pressure within the tank increases, the float member 15 raises the outer end of the lever 20. When the inner end of the lever 20 rests in the lower portion of a slot 23 with which the upright member 21 is provided, further upward movement of the lever 20 raises the valve member v19 to open the pipe 24.

When the pressure within the tank decreases and the float 15 falls in accordance therewith, permitting the valve member 19 to close the opening in pipe 24 and, in case the pressure continues to fall, the lever 20 is actuated about its point of pivotal connection to the valve member 19 until it en gages the pin 22. Further downward movement of the float member 15 causes the lever 20 to move about the'pin 22 as a fulcrum and, when the lever 20 is in the position indicated by a dotted line, to again lift the valve member 19 from its seat. ,The pinand-slOt connection to the member 21 permits this movement. It will be observed that the operation of the modified form of my inventlon is similar in principle to that of the mechanism of Fig. 1.

The principal advantages of my valve mechanism are that it is simple in construction and the single controlling-mechanism operates to control communication of the tank with the atmosphere when the pressure in the tank is either above or below atmospheric pressure.

It will be understood that the respective pressures at which the valve mechanism operates may be adjusted as desired by varying the relative positions of the ports 1n the valve member and the opening in the communicating pipe, b varying the initial height of the column 0 liquid in the U-tube or the dimensions of the various parts, and by varying the weight of the float member or nature of the material therein.

I claim as my invention:

1. The combination with a tank having a vent, of means for openin said vent when the fluid pressure in sai tank exceeds a predetermined value or is below a second and lower predetermined value, said means comprising a movable member having ports for communicating with said vent.

:2. The combination with a tank having a vent, of means for opening said vent when the fluid pressure in said tank exceeds a predetermined value or is below a'second and lower predetermined value, said means comprising a movable member, and pressureresponsive means for controlling said movable member.

The combination with a tank having a vent, of means for opening said vent when the fluid pressure in said tank exceeds apredetermined value or is below a second and lower predetermined value, said means comprising a movable member, and a column of liquid for controlling the position of said member.

'4. The combination with a tank having a vent, of means for opening said vent when the fluid pressure in said tank exceeds a predetermined value or is below a second and lower predetermined value, said-means comprising a pressure-responsive body of liquid and a float member.

5.'The combination with a tank having a vent, of means for opening said vent when the fluid pressure in said tank exceeds a predetermined value or is below a second predetermined value, said means comprising a pressure-responsive, body of liquid and a tubular float member having lateral openings therein for communicating with said vent.

6. The combination with a container having an opening, of means for closing said opening when the pressure within said container is within predetermined limits and forunc-overing said opening when the pressure is without said limits, said means comprising a movable member having a plurality of openings for registering with the opening .in said container.

7. The combination with a tank containing a fluid, of means for connecting said tank to the atmosphere when the pressure therein exceeds or falls below atmospheric pressure by predetermined diflerent amounts, said means comprising a pressureresponsive valve member.

8. The combination with a tank having a vent, of means for controlling said vent comprising a column of liquid responsive to pressure within said tank and a valve member floating on said liquid and operable to open said vent when the height of said column is above a predetermined level and is below a second and lower predetermined level.

9. The combination with a tank having a vent, of means for controlling said vent in accordance with maximum and minimum pressure conditions within said tank, said means comprising a U-tube having liquid therein and having its respective ends connected to said tank and to the atmosphere and a valve member controlled in accordance with the height of a column of liquid in said tube.

1.0. The combination with a tank and deoxidizing means communicating therewith, of means comprising a float-controlled valve member for connecting said deoxidizer to the atmosphere under predetermined maximum and minimum pressure conditions in said tank.

In testimony whereof, I have hereunto subscribed my name this 26th day of April CLARENCE J. RODMAN. 

